Variable isLeft`Const`

isLeft: <E>(ma: Either<E, unknown>) => ma is Left<E>

Returns true if the either is an instance of Left, false otherwise.

Type Declaration

- <E>(ma: Either<E, unknown>): ma is Left<E>
- Type Parameters
  - E
  Parameters
  - ma: Either<E, unknown>
  Returns ma is Left<E>

Since

2.0.0